Hypoxia-inducible factor-2α promotes EMT in esophageal squamous cell carcinoma through the Notch pathway.

ABSTRACT

BACKGROUND: Esophageal cancer is one of the most lethal tumors worldwide. The most common histological type in China is esophageal squamous cell carcinoma (ESCC), accounting for 90% of cases. Esophageal cancer occurs at a high incidence in certain areas, among which China has the highest incidence. Although various therapeutic strategies have been used in clinical treatment, the 5-year survival rate is still not satisfactory, as it is only 15-20%. The reason for the poor prognosis of ESCC is that the distant metastasis easily occurs in these tumors. However, the mechanism of metastasis has not been studied clearly. OBJECTIVES: To investigate the function of hypoxia-inducible factor-2α (hif-2α) in ESCC. MATERIAL AND METHODS: Immunohistochemistry and immunofluorescence were used to detect the expression of hif-2α in tissues and cells. Clinicopathological data from 100 ESCC patients were used to investigate the relationship between hif-2α and prognosis. Cell experiments (Cell Counting Kit-8 (CCK-8) assay and transwell migration assays) were utilized to verify the roles of hif-2α on the ESCC cells. Western blotting was used to explore the mechanism of hif-2α in ESCC. Mouse model was used to clarify the effect of hif-2α on ESCC cells in vivo. RESULTS: The hif-2α was overexpressed both in ESCC tissues and cells, and was related with poor prognosis in ESCC patients. The CCK-8 assay evidenced that silencing hif-2α suppressed the proliferation of ESCC cells, while transwell assay - that overexpression of hif-2α promoted the migration of ESCC cells. Western blot assay indicated that hif-2α regulated epithelial-mesenchymal transition (EMT) through Notch pathway in ESCC cells. Mouse model showed that silencing hif-2α significantly suppressed the proliferation of ESCC cells in vivo. CONCLUSIONS: The hif-2α promotes EMT in ESCC through the Notch pathway.